Twitter is an internet-based communications service, described as offering social networking and microblogging. It enables users to send and read "tweets", which are text messages limited to 140 characters. Such text messages can be publicly visible, so Twitter can be said to be a broadcast service, in contrast to IM services where messages are private and restricted to the recipient. Registered users can read and post tweets, but unregistered users can only read them. Users access Twitter through the website, or by using SMS, or using mobile device apps. Twitter Inc. is based in San Francisco and has offices in New York City, Boston, San Antonio and Detroit.
Twitter was created in March 2006 by Jack Dorsey, Evan Williams, Biz Stone and Noah Glass and by July 2006, the site was launched. The service rapidly gained worldwide popularity, with 500 million registered users in 2012, who posted 340 million tweets per day. The service also handled 1.6 billion search queries per day.Twitter is now one of the ten most-visited websites, and has been described as "the SMS of the Internet."
Twitter's origins lie in a "daylong brainstorming session" held by board members of the podcasting company Odeo. Dorsey, then an undergraduate student at New York University, introduced the idea of an individual using an SMS service to communicate with a small group. The original project code name for the service was twttr, an idea that Williams later ascribed to Noah Glass, inspired by Flickr and the five-character length of American SMS short codes. The developers initially considered "10958" as a short code, but later changed it to "40404" for "ease of use and memorability." Work on the project started on March 21, 2006, when Dorsey published the first Twitter message at 9:50 PM Pacific Standard Time (PST): "just setting up my twttr". Dorsey has explained the origin of the "Twitter" title:
...we came across the word 'twitter', and it was just perfect. The definition was 'a short burst of inconsequential information,' and 'chirps from birds'. And that's exactly what the product was.